body {
    background: #ecf0f1;
}

#_row {
    top: 50vh;
    transform: translateY(-50%);
}

.card {
    border-radius: 6px;
    border: 2px solid rgba(0,0,0,0.15);
    background: rgba(255,255,255,0.5);
}

.drop {
    border: 2px dashed rgba(0,0,0,0.15);
    border-radius: 3px;
    cursor: pointer;
    transition: border .2s ease-in-out;
}

.drop-here {
    color: rgba(0,0,0,0.4);
    display: inline-block;
    padding-top: 20px !important;
    padding-bottom: 20px !important;
}

.hovering {
    border-color: green;
}